This invention relates to an improved method of reducing fouling in filters for industrial water system analytical devices.
In the method of operation of many industrial water systems it is routine procedure to have analytical devices present to analyze parameters of interest concerning the water in the industrial water system. Some of these analytical devices are simple devices, such as thermometers, pH meters, turbidimeters, and conductivity probes, which are measurement devices that involve placing a sensing mechanism of the analytical device directly into the water of the industrial water system.
Other analytical devices are more complicated and require that the water in the industrial water system actually flow through a sample chamber of the analytical device. These more complicated devices include such equipment as streaming current detectors, particle counters, particle sizers, and fluorometers. A streaming current detector is a device capable of measuring absorbable charge in water. A particle counter for water treatment and monitoring directly counts individual particles and tallies according to the individual particle size. The two commonly used methods are light extinction and light scattering. Light extinction directly measures the amount of light obfuscated; the more light blocked, the larger the particle. Assuming spherical particle shape, the light obfuscation is compared to a calibration curve and the particle size calculated and this xe2x80x98countxe2x80x99 is tallied in the appropriate size bin. After counting thousands of particles, a particle size distribution is developed. This is considered a direct method of obtaining the particle size distribution.
A particle sizer measures some metric, such as sound attenuation, and analytically calculates the particle size distribution. This is considered an indirect method of obtaining the particle size distribution. A fluorometer is a device capable of measuring one or more fluorescent signals of one or more fluorescent moieties present in the water. This type of analysis is useful in industrial water systems wherein a fluorescent moiety is present and functioning as a tracer of either the water in the industrial water system or as a tracer of a treatment product or as a fluorescently-tagged moiety that acts as some sort of treatment product.
It has been found that when a sample of water from an industrial water system is moved through an analytical device that it is desirable to filter the water prior to its entering the analytical device. The purpose of filtering is to remove contaminants and other material present in the water that could foul the sample chamber of the analytical device. Filters suitable for this purpose are known to people of ordinary skill in the art of industrial water systems and are commercially available. A known problem with these filters is that during continuous operation they frequently become so plugged with material present in the industrial water system that it is necessary to clean or replace them at regular intervals. Cleaning filters in the piping of an industrial water systems typically involves removing the filter, cleaning or replacing the filter, and then reinstalling the filter in the industrial water system. This type of cleaning is highly labor intensive and time consuming. Additionally, the time interval after clogging and before filter cleaning or replacement, negatively impacts on system performance.
Therefore, it would be desirable to find a way to reduce the amount of fouling present in the filters of an analytical device in an industrial water system.
In a method of analyzing the water of an industrial water system wherein an analytical device is used to measure some parameter capable of being measured in the water of said industrial water system, the improvement comprising using a water movement device that is capable of moving a sample of water into the sample chamber of said analytical device and is also capable of moving the same sample of water back out of said analytical device in a manner such that the filters present in the piping of said industrial water system are back flushed out every time the water movement device moves a sample of water in and out of said analytical device.
The instant claimed invention is in a method of analyzing the water of an industrial water system wherein an analytical device is used to measure some parameter capable of being measured in the water of said industrial water system, the improvement comprising using a water movement device that is capable of moving a sample of water into the sample chamber of said analytical device and is also capable of moving the same sample of water back out of said analytical device in a manner such that the filters present in the piping of said industrial water system are back flushed out every time the water movement device moves a sample of water in and out of said analytical device.
Industrial water systems include cooling tower water systems (including open recirculating, closed, and once-through cooling tower water systems); petroleum wells, downhole formations, geothermal wells, and other oil field applications; boilers and boiler water systems; mineral process waters including mineral washing, flotation, and benefaction; pulp mill process streams, pulp mill digesters, washers, bleach plants, and white water systems; black liquor evaporators in the pulp industry; gas scrubbers and air washers; continuous casting processes in the metallurgical industry; air conditioning and refrigeration systems; industrial and petroleum process water; indirect contact cooling and heating water, such as pasteurization water; water reclamation and purification systems; membrane separation processes, membrane filtration water systems; clarifiers, dissolved air flotation clarifiers, aeration basins, oil-in-water systems, water-in-oil systems, oil separations, sludge dewatering, food processing streams; waste treatment systems as well as in liquid-solid applications, municipal sewage treatment systems and industrial or municipal water systems.
Such waters contain solids (or oils) and liquids and are often once-through systems where the waste water is not recirculated. The preferred industrial water system for the method of the instant claimed invention are those water systems that have a significant amount of solids present in the water. These systems include waste treatment systems, municipal sewage treatment systems, and pulp mill process streams.
Analytical devices suitable for use in this method are those analytical devices that have a sample chamber that must be filled with a sample of water. The water in the sample is then analyzed by the analytical device. The sample chamber of many analytical devices is a xe2x80x9cfill-up and then empty-outxe2x80x9d chamber or the sample chamber can alternatively be configured such that water is continuously moved through the sample chamber.
Typically, the sample of water remains in the sample chamber long enough for the analytical device to analyze the parameter it is designed to analyze. Many times there is a waiting period before the analytical device takes the reading because of the need to wait for the sample to equilibrate. For example, typically with a fluorometer it is necessary to wait long enough for any air bubbles in the sample to dissipate, otherwise the air bubbles could interfere with the analytical device analyzing the water.
For a fluorometer, the typical time period within the sample chamber for the water is from about 5 seconds to 10 minutes, preferably from about 30 seconds to about 7 minutes, and most preferably about 5 minutes.
Analytical devices suitable for use with the instant claimed invention include turbidimeters, streaming current detectors, particle counters, particle sizers, conductivity meters, and fluorometers. The preferred analytical device is a fluorometer.
Fluorometers suitable for use in the instant claimed invention are available from ONDEO Nalco Company, ONDEO Nalco Center, Naperville, Ill. 60563 (630) 305-1000 (hereinafter xe2x80x9cNALCOxe2x80x9d). The preferred fluorometer is a TRASAR(copyright) 3000 fluorometer.
Whatever fluorometer is chosen, the fluorometer must be configured such that the water is sampled, measured, and discharged to the same point. This can be done by simply configuring the fluorometer such that the inlet pipe to the fluorometer sample chamber is the same as the exit pipe and the filter is positioned in the inlet/exit pipe. The reason for the filter is that the inlet to the fluorometer sample chamber has a filter over it to filter out suspended solids so the sample chamber is not contaminated by those solids. It is this filter that tends to foul most often.
The parameter capable of being measured is dependent upon the analytical device. If a fluorometer is used, then the parameter capable of being measured is the fluorescent signal of some fluorescent moiety present in the water of the industrial water system.
If the fluorometer is the analytical device chosen then it is possible to use the fluorescent signal of a fluorescent moiety present in a treatment product. The preferred fluorescent moieties are those known to people of ordinary skill in the art of fluorescent tracers. See U.S. Pat. Nos. 4,783,314; 4,966,711; 4,992,380; 5,006,311; 5,043,406; 5,171,450; 5,278,074; 5,378,784; 5,389,548; 5,411,889; 5,413,719; 5,645,799; 5,658,798; 5,702,684; 5,714,387; 5,736,405; 5,919,707; 5,958,788; and 5,986,030, all of which are incorporated by reference.
The water movement device is typically a pump, configured such that its intake and exit piping are the same pipe. This is contrary to the normal configuration for a pump, so creating a pump like this involves reorienting the piping such that the intake and exit piping are the same. The preferred pump is a piston pump with the foot valve removed such that the intake and exit for the pump are the same pipe. A piston pump suitable for use in this method is available from Blackhawk Pumps and Controls, 21W159 Hill Avenue, Glen Ellyn, Ill. 60137, telephone number (630) 469-4916. Piston pumps typically are manufactured with a foot valve installed, so in order to work in the method of the instant claimed invention, the foot valve must be removed.
With the pump configured such that its inlet and exit are the same, the water sample moved by the pump is first forced through a filter into the sample chamber of the analytical device. The water remains in the sample chamber long enough for the analytical device to complete the analysis. After the water has been analyzed, the water sample is removed from the sample chamber on the back stroke of the pump. The removal of the water sample from the sample chamber forces the water back through the filter and acts to automatically clean the filter. This automatic filter cleaning action means that it is not necessary to manually clean the filter.
Optionally, an air sparge can be used to enhance the evacuation of the sample chamber and to also enhance removal of particulates from the filter on the inlet leading into the analytical device. The use of a commercially available standard air sparge activated by a commercially available solenoid to enhance filter cleaning is a preferred configuration to conduct the method of the instant claimed invention.
The following examples are presented to describe preferred embodiments and utilities of the invention and are not meant to limit the invention unless otherwise stated in the claims appended hereto.